1 Walk back from the car park towards the main road and, 50yds (46m) from the entrance, turn right onto the waymarked byway. To begin with there are fine views across the Weald, but soon the track drops into the trees and comes to a junction at an old Second World War pill box. Swing right here, and follow the byway as it bears left past the old chalk pit where Agatha Christie's car was abandoned in December 1926. Look out for a turning on your right, then carry straight on for a further 200yds (183m).

2 Turn left onto the unmarked bridleway, passing Water Lane Cottages on your right. Continue to the fork at Timbercroft, and bear right onto the footpath towards the Silent Pool. There are dogs and cats living here, so it's best to have your own dog on a lead. Fork right again after 100yds (91m), onto the narrow, signposted public footpath. Take care as you cross the quarry access road, then continue as far as the A248.

3 Cross over, turn left onto the footpath which runs just inside the hedge, and walk up to the A25. Turn left at the top, re-cross the A248, then follow the A25 footpath for 100yds (91m). Now cross the busy main road and join the footpath, up past Sherbourne Farm. Just beyond the farm entrance, your waymarked path is crossed by the broad, gravelled track leading up from the car park. Fork right here to visit Sherbourne Pond and the Silent Pool.Return to the narrow, waymarked path to continue your walk. The path climbs gently at first, then plunges into the Boxwood and begins the serious assault on the Downs. It eases off towards the top, and meets the North Downs Way National Trail at an acorn waymark.

4 Turn left onto the North Downs Way, then keep right 300yds (274m) further on, as another track forks off down the hill. Now you can settle into your stride for a mile (1.6km) of level walking back to the busy A25, bang opposite the car park where your walk began.

In an extraordinary episode redolent of one of her own novels, Agatha Christie dominated the British papers during the first two weeks of December 1926. She never mentioned the affair in her autobiography, and the motive which fuelled 11 days of intense police and media activity has remained an enigma long after her death.

Agatha Miller married Colonel Archie Christie late in 1914. After wartime service in the Royal Flying Corps, Archie returned to civilian life when their daughter was born, five years later. Agatha's first novel was published in the following year and, by the mid '20s, income from her books helped the couple to buy their own home at Sunningdale in Berkshire.

But material success masked fault lines in the couple's relationship. The war years could not have been easy and, just possibly, Archie felt threatened by his wife's success. She put on weight after their daughter's birth, whilst he found consolation - and romance - on the golf course. On Friday, 3rd December 1926, there was a furious row as Archie told Agatha that he would be spending the weekend with his mistress, Nancy Neele. Divorce was inevitable.

That night, Agatha left her sleeping daughter and treasured dog, climbed into her bullnose Morris, and disappeared into the night. The following morning, the novelist 's car was found abandoned by the chalk pit that you'll see in Water Lane, near the start of your walk. But Agatha Christie was gone.It was national news. Whilst the police scoured southern England and questioned Archie on suspected murder, the Daily News offered a £100 reward for information. The story remained in the press and, on Sunday 12th, thousands of people converged on Newlands Corner to search for Agatha's body. Meanwhile, almost 24 hours after her disappearance, Agatha Christie had calmly booked into a Harrogate hotel under the assumed name of Teresa Neele. Despite the national hue and cry, ten days elapsed before the police located her. Archie was in the clear, deflecting reporters by explaining his wife had amnesia, and the couple fled to Abney Hall in Cheshire, home of Agatha's sister.

This bizarre affair has been shrouded in mystery ever since. Christie herself refused even to discuss it and, after her death, there were unsuccessful attempts to suppress a film adaptation of the story. The unsolved mystery was featured on BBC television in 1997, and the programme included an appearance by author Jared Cade. His subsequent book claims that the entire episode was simply Christie's attempt to embarrass her husband and sabotage his weekend with his mistress. It is, at least, a convincing theory.

What to look for

Many legends surround the tree-shaded Silent Pool, close by Sherbourne Farm. Even in high summer you'll feel a slight chill in the air, and there's something rather unearthly about its clear, bluish-green water. Believe, if you will, that a young maiden was taking her customary dip when the wicked King John rode into the water to carry her off. Despite her brother's efforts to save her, both brother and sister perished, 'locked in each other's arms in the tranquil crystal depth'. It's said that on moonlit nights a white form bathes here still, until with a hideous shriek it disappears below the dark surface.

Where to eat and drink

While you're there

If you're interested in animals, farming or wildlife, then you'll enjoy a visit to Sherbourne Farm, adjacent to the Silent Pool on Shere Road. It's no theme park, but a family run working farm where you can see seasonal displays ranging from lambing, shearing and calving to planting and harvesting. Children especially enjoy feeding the hens, ducks and geese.